Peanuts are the seeds of the peanut plant (Arachis hypogaea), a legume that flowers above ground and then pushes its developing pods into the soil to ripen, hence the name groundnut. Botanically they are related to peas and beans rather than to tree nuts, though they are eaten much like nuts.
Roasting gives peanuts their deep, nutty aroma and crunch, which pairs naturally with chocolate. In M&M’s Peanut Chocolate, a whole roasted peanut sits at the centre of each piece, covered in milk chocolate and a coloured sugar shell; peanuts make up 23% of the recipe.
Peanut is one of the major food allergens and must be declared on labels. Products made on lines that also handle peanuts often carry a “may contain peanuts” note as well.

